Process of dyeing and printing in anilin-black.



Marten "rates Patented May 5, 1903.

I ATENr FFICE.

PROCESS OF DYEING AND PRINTING IN ANlLlN-BLACK.

$1 GIFI0ATI0N' forming part of Letters Patent N 0. 727,292, dated May 5, 1903. Application filed January 20, 1903. Serial No. 139,813. (No specimens.)

1'0 all whom it may concern:

Be it known that I, FRIEDRICH CLEFF, a subject of the Emperor of Germany, residing at Rauent-hal, near Barmen-Rittershausen, in the Kingdom of Prussia, German Empire, have invented new and useful Improvements in Dyeing and Printing in Anilin-Black, of which the following is a specification.

My said invention relates to improvements in dyeing and printing in anilin or true black.

In such arts an oxidizing process is employed consisting in impregnating the fibers with a bath of a solution of an anilin salt, chiefly anilin hydrochlorate, with oxidizing agentssuch as nitrate of copper, chlorate of soda or of potash-drying, steaming, and chroming. In this treatment the fibers are, however, much weakened by the mineral acids which are liberated in the steaming, and the shade of the black color thus obtained is so far alter-able that it easily passes into greenthat is, the black soon acquires agreen cast. According to the process described in the speci fication of United States Patent No. 452,324 a portion of the mineral acids was replaced by an excess of hydrofluoric acid. Hydrofiuoric acid alone is not sufficiently energetic, and the mineral acids were needed to start the oxidation, which is completed by the hydrofluoric acid. That process possesses the advantage that the fibers are subjected to a minimum amount of weakening by the free hydrofluoric acid; but even in such a process, like when hydrochloric acid is used, the black still possesses a somewhat greenish shade, and the working of the process is very disagreeable on account of the corrosive properties of the free hydrofluoric acid.

According to my present invention I overcome the abovementioned defects by using formic acid (OH O or salts thereof in the dyeing and printing process. By using formic acid I avoid the need for mineral acids, since formic acid acts quickly and powerfully. It does not weaken the fibers. The black ob tained by its use is intense and free from greenish cast, while the fabric acted on has a beautiful touch and brilliancy.

By way of example I give the formula for a bath for a woven fabric consisting of silk and cotton.

Forty grams chlorate of potash, twenty grams sal-ammoniac, twenty-five grams nitrate of copper are dissolved in seven hundred grams of water, and after cooling I add to this solution one hundred grams of anilin To the cooled thickened resulting mass I add' twenty-five grams of nitrate of copper dissolved in fifteen grams of water, one hundred grams of anilin, and two hundred grams of formic acid, (twenty-six per cent. strong.)

The printing, steaming, &c., are carried out in the usual manner.

Wool requires a preliminary treatment with chlorid of lime, permanganate of potash, &c., even when using formic acid.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is The process of dyeing and printing in anilinblack which consists in exposing fiber or fabric to the action of formic acid along with the usual solvent, thickening and oxidizing agents.

In testimony whereof I have hereunto-set my hand in the presence of two subscribing witnesses.

FRIEDRICH OLEFF.

Witnesses:

OTTO Konie, J. A. RITTERSHAUS. 

